CPC B61L 1/187 (2013.01) [B61L 1/185 (2013.01); B61L 1/188 (2013.01); B61L 23/044 (2013.01)] | 13 Claims |
1. A track circuit for a railroad track block, said track circuit comprising:
a first occupied track device connected to rails of the railroad track block at a first portion of the block; and
a second occupied track device connected to the rails of the railroad track block at a second portion of the block, said first and second occupied track devices being configured to:
detect a presence of a train on the rails of the block using a DC function, and
once the presence of the train is detected, determine an amount of unoccupied track behind the train using an AC function,
wherein said first occupied track device is calibrated in accordance with an impedance of the second occupied track device, and said second occupied track device is calibrated in accordance with an impedance of the first occupied track device, and
wherein said first and second occupied track devices are configured to determine one or more broken rails in the block, while the train is within the block, based on one or more impedance readings along the rails of the track.
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